Hemostasis valves are well-known, being currently used, for example, in arterial catheter introducers, used with catheters for performing percutaneous transluminal coronary angioplasty (PTCA), as well as catheters for angiographic procedures, for example where x-ray contrast fluid is inserted through a catheter into the coronary artery. The hemostasis valve is typically used to prevent the leakage of blood out of or around dilatation and other catheters which particularly enter into an artery, to prevent the reverse seepage of blood out of the patient into the operating field. Typically, hemostasis valves are conventionally positioned at the proximal ends of catheter introducers, which are used in conjunction with guide wires to facilitate the entrance of catheters into an artery or other blood vessel.
Numerous types of hemostasis valves are known. By way of example, see Stevens U.S. Pat. No. 4,000,739, Matsumoto et al. U.S. Pat. No. 4,610,655, Weinstein U.S. Pat. No. 4,626,245, and Hillstead U.S. Pat. No. 4,798,594.
In all of the previously cited patents, the hemostasis valves include an elastomeric partition of a solid, nonporous material which defines a slit through the partition, to facilitate the advancement of a catheter or guide wire through the hemostasis valve.
By this invention, a significant modification is provided to a hemostasis valve for use in a medical instrument such as a catheter introducer. Improved ease of advancement of the catheter through the hemostasis valve partition can be achieved, while good sealing against blood leakage is provided. Furthermore, with this invention it may not be necessary to provide a slit or other aperture through the elastomeric partition used in this invention, with an advancing probe such as a guide wire forming its own aperture, so that a better sealing fit is provided between the advancing probe and the partition as the probe is advanced through the hemostasis valve.